In test laboratories plug and jack shielded BNC and TNC connectors may need to be provided in back to back relationship, in the form of plug to jack connectors, plug to plug connectors and jack to jack connectors. Shielded plug connectors comprise an externally metal shielded dielectric having a central bore, in which is a contact element having a mating portion in the form of male electrical terminal, usually a pin terminal, which will usually project into a skirt defined by the dielectric. In shielded jack connectors, the mating portion is in the form of a female electrical terminal, usually a receptacle terminal for mating with a pin terminal, and which usually lies in a plug portion defined by the dielectric.